反应详情

To a cooled (5° C.) solution of 2N sodium hydroxide (10.0 L) was added the compound of step A (244.1 g) in one portion. The solution was warmed to room temperature over 2 hours using a warm water bath then recooled to 5° C. and the pH adjusted to 2 with 6M sulfuric acid (1.2 L). The mixture was extracted with 3×3.0 L of ethyl acetate, washed with brine (1×2.0 L) dried over sodium sulfate and filtered. Concentration in vacuo gave a tan solid. Trituration with hexanes, and filtration afforded 173.7 g (58% yield) of the title compound. M.P. 136° C.-137° C.

1. customthen recooled to 5° C.
2. extractionThe mixture was extracted with 3×3.0 L of ethyl acetate
3. washwashed with brine (1×2.0 L)
4. dry with materialdried over sodium sulfate
5. filtrationfiltered
6. concentrationConcentration in vacuo
7. customgave a tan solid
8. filtrationTrituration with hexanes, and filtration